Selective nail feed mechanism



y 1934- H. E. TWOMLEY 1,956,935

SELECTIVE NAIL FEED MECHANISM Filed April 29, 1931 2 Sheets-Sheet l May 1, 1934.

H. E. TWOMLEY SELECTIVE NAIL FEED MECHANISM 2 Sheets-Sheet 2 Filed April 29, 1931 3/ MINI W ZM A fforney Patented May 1, 1934 UNITED STATES PATENT OFFICE The Estate of George D. Parker;

Parker, executrix Clara B.

Application April 29, 1931, Serial No. 533,655

Claims.

This invention relates to box nailing machinery, such for example as disclosed in the patent to Parker, 993,545, issued May 30, 1911.

In such machinery, the nails are urged through 5 the boards forming the box by punches that are urged against the nail heads after the nails are positioned in the chucks in which the punches move. The supply of nails to the chucks is usually accomplished by the aid of a series of chutes or delivery tubes that lead from a nail distributing mechanism, and that serves to supply one nail at a time to the tubes. By appropriate synchronized mechanisms, the feeding of the nails is made to conform in time to the nailing 0 operation.

Usually, open boxes are made by nailing a bottom and two sides to the two end pieces. Thus this operation has a plurality of phases corresponding to the number of sides, tops or ends nailed, which phases are either simultaneously or successively effected. In the instance just discussed, there are three phases corresponding to the nailing of the two sides and the bottom of the box, although a larger or smaller number could be used, depending upon the character of the boxes made.

The feeding of the individual nails into the delivery tubes is accomplished usually by the aid of strippers and nail picks. The strippers are 3 gravity guides leading from a nail pan (usually oscillated to keep the nails therein from packing or massing and causing them to find their way into strippers in the bottom of the pan). These strippers usually have a central groove serving as a a guide for the nail body, and narrower than the nail head, so that each stripper thus supplies a continuous row in single file to a nail pick. The

nail pick in turn is actuated in proper sequence to cut out the first or lowermost nail and to drop it into the delivery tube.

Such nail pick mechanisms are shown in two of my prior patents, No. 1,409,801, granted March 14, 1922, and 1,412,984, granted April 18, 1922.

It is apparent that the distribution and numoer of nails for any one operation need not be the same as for any other operation of the cyclic phases. Thus, the bottom of the box requires nails at all four edges, while the sides require nails along three edges only. Furthermore, the dimensions of the sides and bottom may be difierent, necessitating different nail spacings. In order to take care of this selection of the correct number and arrangement of the nails, a selector mechanism is used, which can be set to cause any combination of the nail picks to be active for any one of the series of nailing operations. This selection can be accomplished for example, as illustrated in my prior patents; and my present invention relates to a further form of selector which is simple and inexpensive and which can be very easily adjusted to take care of any arrangement of the nails.

It also sometimes happens that a badly formed nail jams the picker mechanism so that it cannot operate. In the prior devices, precautions for taking care of such occasions involve relatively expensive and complicated mechanisms, and the relieving of the jam requires taking the mechanism apart, especially since the inactivity of the jammed pick may disturb the sequence of operation of the picks. It is accordingly a further object of this invention so to arrange the nail picks that when any of them become jammed, the selective arrangement is not disturbed except that the jammed pick stays inactive until relieved. This I accomplish by providing a simple form of yielding mechanism that cannot readily get out of order, which, when a jam occurs at any pick, does not in any manner hinder the operation of the other picks.

It is a further object of my invention to provide a nail pick structure that ejects the nails from the picks positively and in a simple man ner.

It is a still further object of my invention to provide a pick mechanism that is positive in its action, and that is not liable to become inoperative upon accumulation of dirt, saw dust, and soapstone, to which such mechanisms are subjeeted.

My invention possesses many other advantages, and has other objects which may be made more easily apparent from a consideration of one embodiment of my invention. For this purpose I have shown a form in the drawings accompanying and forming part of the present specification. I shall now proceed to describe this form in detail, which illustrates the general principles of my invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of my invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a fragmentary plan view of a nailing machine incorporating my invention, showing the nail picking apparatus in normal receiving position;

Fig. 2 is a detail perspective View, taken along plane 22 of Fig. 1;

Fig. 3 is a detail section taken along plane 3--3 of Fig. 1;

Fig. 4 is a view similar to Fig. 1, except that the left hand pick is shown in the act of dropping a nail and the right hand pick is shown in the act of relieving a jam caused by an irregularly formed nail;

Fig. 5 is a view of the left hand end of the mechanism shown in Fig. 1, illustrating one manner in which motion can be imparted to the pick mechanism;

Fig. 6 is a view similar to Fig. 5, but of a slightly different form of mechanism for imparting the required motion; and

Fig. '7 is a diagrammatic view of a nailing machine selector and its associated parts.

It is of course to be understood that although only two nail picks are shown on the drawings, there are usually a much larger number of such picks, to take care of the maximum number of nails to be driven in any one operation.

The nailing machine as diagrammatically shown in Fig. 7, includes one or more oscillating nail pans 11, driven by appropriate links from the main source of motion, to keep the nails in free flowing condition. Nail strippers or guides 12 incline downwardly from the pans 11 and toward the picks 13, which deliver the nails to funnelled tubes 14 leading to the nail chucks. The nail picks 13 are actuated by a mechanism 15 which will be later described.

Referring now to Figs. 1 to 4, each of the strippers 12 has two sides defining a central guiding groove 15 that accommodates the body portions of the nails 17, which progress by gravity toward the picks 13. The supporting frame members 18 serve in general to provide a support not only for the picks 13, but also for the shaft 19 that operates the picks. Each of these picks has a nail head receiving socket 20 that has a notch 21 to accommodate the nail shank. The walls of socket 20 slope forward and in the receiving position of Fig. l, the socket is opposite its corresponding stripper and holds the first nail of the row by its head. The slot 21 is just deep enough to accommodate one nail and no more. The picks 13 are pivoted on the shanks of screws 22 fastened into the pick bar 23 extending between supports 18. Each of these screws have a smooth shank portion the bottom of which forms a shoulder contacting the bar 23, which shoulder extends around the threaded portion.

It is apparent that as the picks 13 are rotated in a counter clockwise direction about the pivots 22, the nail in socket 20 will be moved to the left, and during this movement the front edge of the picks will hold the row of nails in strippers 12 against movement until the picks assume the receiving position of Fig. l. The nail 1'7 thus moved toward the left is urged against the edge of pick bar 23 as shown by the left pick 13 of Fig. 4. On continued movement of the pick, the nail 17 is ejected from slot 21, because the socket of pick 13 moves away from the nail 17, which is prevented from further movement by the bar 23. The nail 1'7 then drops into the funnel of the delivery tube 14 and is fed to the usual nail chucks and in position to be driven into place by the corresponding punch.

In order to position the picks l3 accurately at their nail receiving positions of Fig. 1, use can be made of a stop pin 24 contacting with a shoulder on the right hand side of each pick 13 and driven into bar 23. The rotary movement of the picks 13 to cut out a nail from its associated stripper 12 is provided by a positive drive mechanism which will be later described. The return of the picks to contacting position with stops 24 is accomplished by a yielding or spring arrangement.

Thus a spring pressed plunger 25 has a conical tip which is accommodated in a corresponding socket 26 in the body of pick 13 and on the other side of pivot 22. This plunger is free to slide in the upright leg of a bracket 27, the horizontal leg of which is fastened to the top of pick bar 23. A compression spring 28 embraces the plunger 25 and urges it against the pick 13. The spring is confined between the vertical leg of bracket 27 and a flange 29 on plunger 25.

In order to actuate the picks 13 against the force of their respective springs 28, so as to move a nail 1'? over a delivery tube 14, use is made of a cam and roller movement. For example, the end 30 of each pick 13 can be formed with a curved cam surface, arranged to cooperate with cam rollers 31 that move downwardly past the cams to urge the picks in a counterclockwise direction. These rollers are rotatably supported on screws or bolts 32 that are radially disposed on the rotatable roller shaft 19. As shown most clearly in Fig. 3, each screw 32 has a lock nut 33, forming a shoulder bearing for roller 31. The screw also has a straight shank portion serving as a shaft or pin for the roller 31. The outer surface of nut 33 and the lower surface of the head of the screw define a space wide enough to accommodate the rolls. By screwing the bolts 32 into radial tapped holes in shaft 19, the rolls 31 can be securely although detachably supported on shaft 19.

In the present instance, the shaft 19 is shown as having a hexagonal portion where it supports the roller screws 32 in rows along alternate faces of the hexagon; but of course other forms of shafts could be used. Furthermore, in this particular instance, actuating shaft 19 is intended to be rotated in step-by-step order by a succession of movements, each movement equal to a third of a revolution. Thus for a complete revolution of shaft 19, the nail picks can be operated as often as three times; this number represents the number of phases of operation of the nailing machine and may correspond to the nailing of the two sides and the bottom of the box. However,

by making the intermittent movement of shaft 19 greater or less than respectively less or more phases of operation could be taken care of.

It is thus apparent that for each intermittent movement of shaft 1.9, each pick 13 can be actu- I ated by a roller 31 sweeping across the face of cam 30. When this occurs, the nail pick 13, as illustrated in Fig. 4 by the left hand pick, is actuated against the force of spring 28 to out out a nail.

As the roller 31 passes beyond the cam 30, the

spring 28 and plunger 25 serve automatically to return the pick 13 to the receiving position of Fig. 1. It is also a simple matter to render any of the nail picks 13 inactive during any of the intermittent movements of shaft 1 complished by merely removing a screw 32 with its associated roller 31, from shaft 19, said roller corresponding to that operation where the associated pick 13 is to be left inactive. For example, in Figs. 1 and 4 are shown empty tapped holes 34 where the roller screw 32 has been omitted. Thus the proper number and distribution of the nails for each operation can be predetermined.

The intermittent actuation of shaft 19 can be accomplished in sychronism with the nail driv- This can be acing operation. For example in Fig. 1 and Fig. 5 the shaft 19 is shown as carrying a ratchet 35 having three teeth. A pawl bar 36 is freely rotatable on shaft 19, and carries a pivoted pawl 38 urged by spring 39 to a tooth engaging position. It is apparent that if bar 36 is oscillated through 120, about shaft 19, this shaft will be given a movement of 120 for each oscillation. This oscillation can be accomplished by the aid of connecting rod or link 37, pivotally connected at one end to a clevis 40. This clevis is adjustably supported on bar 36. Connecting rod 37 can be actuated from the main source of motion of the machine so that it is reciprocated through a cycle in timed relation to the nail driving operation.

In Fig. 6 another form of mechanism for driving shaft 19 is illustrated. Here a sprocket wheel 41 is shown attached to shaft 19. It is rotated through 120 by a chain 42 connected to a drive sprocket (not shown) which is driven in timed relation to the nailing operation. For example, the drive sprocket can be one which makes a complete revolution for each machine operation, in which case it should be only one-third the size of wheel ll to rotate it through 120".

It happens occasionally that an improperly formed nail is fed to a stripper 12 which jams the picker mechanism. Precautions must be taken to prevent the machine from breaking when this occurs. In the present instance, such jams are easily relieved by simply making the bearing 43 of each pick 13 in such a way as to permit relative movement between it and the pivot 22. This can be accomplished by making this bearing 43 either slotted or as a half-bearing.

Now let us assume that there is an improperly formed nail passed to the pick 13, such as nail 44 at the right hand pick of Fig. 4. Then as roller 31 acts on this pick, the nail 44 being jammed, the pick 13 merely moves about this nail as a pivot, this being permitted by the bearing 43. Spring 28 is compressed by this action. The half-bearing 4:3 in conjunction with spring 28 and plunger 25, permits the pick to be yieldingly moved by roller 31 even if a nail is jammed in the pick.

To state the matter in another way, the halfbearing structure makes it possible to move the pick 13 about either of two fulcrums; the pivot 22 or the jammed nail 4 1. When there is no jam, the spring 28 and plunger 25 effectively prevent relative lateral movement between the half-bearing and the pivot; but the spring 28 yields in response to a jammed condition, as illustrated by the right hand pick 13 of Fig. 4.

It is to be noted that there is no disturbance of the selection of the nails 17 when there is a jam, except that the jammed pick stays inactive. Furthermore, as soon as the jam is corrected, the mechanism operates to select the nails in proper order. The pick mechanism is also such that should any part be broken it can easily be replaced without removing any other part of the mechanism. Also, as only one spring is used for a dual purpose the construction is greatly simplified.

I claim:

1. In a nail feed mechanism, a movable nail pick, means engaging the pick to move and yielding means normally confining the movement of the pick to nail pickin position, but allowing the pick to be moved by the engaging means when the pick is jammed, said movement being a rotation about a point on the pick, where the jam occurs, as a pivot.

2. In a nail feed mechanism, a rotatable nail pick, means for rotating the nail pick about an axis, and means yieldingly confining the movement of the pick about the axis, said yielding means being adapted to yield to the full action of said rotating means when said pick is jammed.

3. In a nail feed mechanism, a rotatable nail pick having a nail engaging part as well as a bearing part, a pivot for the bearing part, said bearing part being so formed that relative lateral movement between the bearing and the pivot is permitted, yielding means opposing said movement, and means for imparting rotational movement of said pick about said pivot, said yielding means being adapted to yield to the full action of said rotational imparting means when said pick is jammed.

4. In a nail feed mechanism, a rotatable nail pick having a nail engaging part as well as a bearing part, a pivot for the bearing part, said bearing part being so formed that relative lateral movement between the bearing and the pivot is permitted, yielding means opposing said movement, and means engaging the pick to move it about the pivot and in opposition to the yielding means.

5. In a nail feed mechanism, a rotatable nail 100 pick having a nail receiving recess adjacent an edge thereof, as well as a central bearing part,

a pivot for the bearing part, said bearing part being so formed that relative lateral movement between the bearing and the pivot is permitted, 105 a spring pressed plunger operating to oppose said movement as well as to return the pick to the nail receiving position, and means engaging the pick for rotating the pick away from the nail receiving position and to a nail discharging position.

6. In a nail feed mechanism, a rotatable nail pick having a nail receiving recess adjacent an edge thereof, a pivot for the pick, means engaging the pick to move the pick from a nail receiving position to a nail discharging position, and means whereby said pick is permitted to move either about the pivot as an axis or about an axis formed by a jammed nail.

'7. In a nail feed mechanism, a rotatable nail pick having a nail receiving recess adjacent an edge thereof, a pivot for the pick, and engaging an elongated bearing part of the pick to permit relative lateral movement between the pivot and the pick, yielding means opposing said relative movement, a stop against which the pick is urged by said yielding means to position the pick in nail receiving position, and means for engaging the pick to move the pick away from the stop and normally to rotate the pick about the pivot, said engaging means serving to cause said lateral 3 movement when the movement of the nail receiving recess is prevented by a jam.

8. In a nail feed mechanism, a rotatable nail pick having a nail receiving recess adjacent an edge thereof, said pick also having a slot serving as a central bearing, a pivot in the slot, a stop for positioning the pick at nail receiving position, a spring pressed plunger engaging the pick and urging it against the stop as well as causing the pivot to engage one end of the slot bearing, and means engaging the pick at the end opposite the nail receiving recess to rotate the pick away from the stop, or to cause lateral movement of the slot and pivot when the pick is jammed.

9. In a nail feed mechanism, a series of pivotally mounted picks, each having a nail receiving recess, a stop for each pick to position it in nail receiving position, resilient means for urging the picks against the stops, and means for rotating the picks, the pivotal mounting of the 5 the picks against the stops, and means for rotating the picks, each of said picks having an elongated slot bearing permitting lateral movement of the pick with respect to its pivot when the pick is jammed.

HERBERT E. TWOIWLEY. 

